SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec09ca691aad2238332b2e7846c12ab03772f0561aa239e5817e4d61befd7d58' 
  AND token = 'EW8tUQe9R5jJ+pec0Qu8HjACrbN1mXz9Ri2qPk3Y+L0=' 
  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"
    }
  }
}