SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5db1928f0769c00c04854f5b911c7692cae41ed27c2157347a6bd4d11b130ca' 
  AND token = 'nAvkRfRvOfShwIXQtti8nY/lBfJ/7U4dtmog3ewMjQA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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