SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54f23da1c55c62f798f13a83564d23701be22314ddb94a90c09151c19ee637e9' 
  AND token = 'USooL+DFDkqLUL4TXYFJOpyjYpCIOovBuySY7XZR7Ys=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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