SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4acf4fb6322f5c95691fd40f924e5613cec803cc232dbea2e8b1da6f40861fc0' 
  AND token = 'IGvar8kesLVbW3feNUNn+1Fir/91ZexsisOZJdNlofA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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