SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c2ddf23bb2b26acc693b119b8619558af8f51dc0f98b59b84348e2088c86cb6' 
  AND token = '7KjLp7Fv7n0dhj29eS/hQUnVtAX981jmYZJozWJq208=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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