SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe8212b89bcd7465291fa332137d193cc3e08d4e6c8641874c6a8d3787849d3d' 
  AND token = 'mFvZqi9epWuMcCnKkBdc82wDVxAKX0ag2/WYNbjhVnY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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