SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db58503a86e50689c8b63e96d87a2395bb5e35512252e555efa4910b0f417c0d' 
  AND token = 'eveCV/qvgL/hrjwzWaxCIhSTP8IvJXFQ/fdFbhw8wjA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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