SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '64ca52af3420ea86af085bfa2c15d880897546f959e9973480c75d1522b4ac87' 
  AND token = 'dqFfwLVO5EPXVy1kfYRNsYoTRW/Vb9MsoFj2DODIC2U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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