SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b7a6bbce9cf53f4dbf43a315145cd096e0e25184cdfad73f538eae494b9af6e1' 
  AND token = '418JoJUdwMZTee59ZM5xmuZNob1pP6g7XqgcIem9U48=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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