SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ada702055d323b250a5d7261b610ec873ff1e3ff57d355fab4583fa884ebce1' 
  AND token = 'ghyO16Sc2fo4UsAEIh4QW9AjlaTMFVLB1UN+UFgwyY4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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