SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c55f552486d8dd0deef9ede4c6cdd25ed289bd4d8b87d0cfbe7721ce92e48ce7' 
  AND token = 'cN2pzpvSyVWZYvvVMvNZJkaU43NK5vK4fpQkoeT7nQ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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