SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5fe73b3a1c4db89a94935bed048dcfcc162ca0af99fc3e507466627a412ef41e' 
  AND token = 'lnLomS1P9UuwesEk36yoO9fo+O5TFOXU3NknY23XcMk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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