SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c8713fa4095a2bb7f114fbac73532a63724a07fd91a0447139ca49c7c3685424' 
  AND token = 'xu1NKOBWDqfC7+cqxgwYFkqvUp0xyzwX53bKiT/TilI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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