SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc8ff48be61187f1e603700b569cc968085b55b659b3ad64e60003d9709cc97a' 
  AND token = 'UtvzvsvfIUX1J78VsjFsJoYXfRbvmHj76eAKede01OI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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