SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4cc59fa5cdfaf97e525681f4648d486203eb639262583028bfe794273fa61598' 
  AND token = 'vJyf7A+p/Xyta7cbmgxUEpaMTLLtzxNjPh+t9IxooTk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00009

JSON explain

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