SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96b9b9db1ac137e536862ac76a28fe9e8a005062f802914aec004643abd96083' 
  AND token = 'M5kdeKWodqGs+wrJ3aTnerUVjntztVtoyQzOJ2WyDZw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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