SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '869c8af78600fc835d30e337d1241bb400b1a1ba67842aae0905c936cb7b529e' 
  AND token = 'MqsAU8TGQ8RQnNPJ4u2YdFuU+eEaOecTY0CP/rbHzBQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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