SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8124794ca511dbf252d512275795473349e06cd253d9d0aeac851b72d4a82368' 
  AND token = '9N2NT4U9e1M/ql7AqkwYfdBhydhyWPdcMsiayJjQF+I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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