SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '97c9f7864d1c71d54103aec644bbbad18529a249e6b2b0275b5a204e699f1339' 
  AND token = '3COpF8MyrKukqJM46N+n/zcYYnCGZjMoiHqVHFLgtww=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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