SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '253d85da164da98fe5b5a8b3e0deff8e02aea65bbba31044668e42039c0c69b7' 
  AND token = 'bH7b2Lawt5kOPGbTQmtdaIVVqwv441Wy0zXNB8nTxy4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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