SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '833f09dc7162954bc30507533aa880dbd0348fb13dd1bf7785c483432f6fe07b' 
  AND token = 'gThh8wdMBL2CBh9NvNd05kD91TGJpbVBLpvlsX6IGiE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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