SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd8f159362d26841174c2c2ff631623007ba60af29143a122b03adb50c9e53dd' 
  AND token = 'LlgOk64ADcKKjpNEX53dH+8iR0+UIib7zzORvi8p0KQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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