SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a5cfcf4c7878a66f4df32e780d13a1df4c9c85cb62c44c5500e391752d5b02e' 
  AND token = 'OuMZZIhWvz66IKLwlurmHPsBv6iU1tYuwMM3mCKG9ow=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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