SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb52e044f644b43f3794bf7da46c7f243717f02e7518a97a7f81b3f69dc3a9be' 
  AND token = 'GvsMBxUvkzvSeBLjDhNkCi0ls7qR3rGEP9JWRKEOx40=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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