SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8488338f74a7f6770f7bfa7545be5a63bb9d0015896272a6e937b59ce2ff2bf' 
  AND token = 'gMla8KR7+IByOgQhYEtgqSY91D/6sV+ClCYVuL5d6CY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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