SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd27b3845947fafbf6a9970edefa3e36fe86c74fd237a1299d4b2903d32dc7d07' 
  AND token = 'y3cEZyFCBshgpKDRArdo2jz4vgfVbsZ+uhDJGYeGkMI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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