SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75ae148fabbea46088eb3e531e9cb253581252fd93183bf14fc93822b2da3f21' 
  AND token = '8og6leBPeEZr3UqV2Ctg81NeUkHshCdZZCRMr4Dg0fg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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