SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c4db6e9480b89b32617c92f6d4e9579fe76f70a304b8818ac219a4efce41307' 
  AND token = 'kpu7jAFfe/i01jZ3/J/HNIIlfqUZGZwoHSoaSGkNhpA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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