SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a564800facd7eb233f944bc42cbe5e56c935e474e975037d2d24e40de13c7dd7' 
  AND token = '+dHGDTiwMCAp57qe6+NUxPQlZGk3Dn1dg44ntt4HIZQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00007

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}