SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57a63d1c37413a26140689baf72a9a4c45c4e187b73b3d5ffc49168f681bd265' 
  AND token = 'opEFJAErAAVHzIKXFFtQlzk6r2p5cauVAlxGN78nENU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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