SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'deae06e4986bd185f9e84ae81f9b78710505174c6b21c6112bc6362f8141db22' 
  AND token = 'YLbg3fUO4pwyQlKt667RhvoB1fkT7Ocu+JXHVDvZPFA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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