SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '14dbcb86103386ab2b16f810e344be75797759fdbe25ae42dee7f58e8ba65666' 
  AND token = 'OxJGuwz2SVb7kz5X9iQKFZTLCfZCaqiu8pE2q8xq5Ug=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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