SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '59811b7c2cbcba74bbfd490668afa5633f6d7acf85252fa7cac4363ac7596d0b' 
  AND token = 'kIoqpJiC5HCPKL2lMeiWeT+rKe4vgXP1UX8m4RJS1CA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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