SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd28b49db136aac0a45b12791e8b0f21676ccb8187ee7307fdb99b7a6826f5d65' 
  AND token = 'FpgFZNA1CMJR2hNVb82ywLimYuCtmNvHkSU/nZduLqo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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