SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '322aae541f98c5cc587173f5d0f06967651b598ae1f380529c594c5ec24540c1' 
  AND token = 'q+JId7Dh3IKTeoeVffwxqBjY0hwiqwsFmh5LBtCXETM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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