SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '513b982f9fa82724bb19690f6894dec778fd2525669405083f3106b91d28df86' 
  AND token = 'mmKa3VbudjiVRIntoeGmJ/R0lROyMbqvqwQExelVyOQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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