SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e46a0548af47ac58859c8eb2515de84650e3375347ad30da0db1cdea2a6abe70' 
  AND token = 'dikhaiEnqL1o0EjTKaYDMO2oOwh/svfpTM722CH9HK8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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