SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '94d898e3307f29d27b58252b53e53cb713271bc0b3706bdb6f5608a2953e4222' 
  AND token = '0YmN4O13scK9/667CjA80urqFoCGdHt+z2wSmZJVqhM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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