SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ec58929a243697625f7634760d71e17c0990129362bf50730c1b3e1b05c74cf' 
  AND token = 'ycCFLHBlPgPLdKfvwHkGFXusw16Qm9Qfi8Lmo/KgBXA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}