SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f03abd9c5b414a61701698b7e9319fcc87e1e8c7e1a80ed69b30047c9d68b67b' 
  AND token = 'trjmM87RIDDPeWwnNthZhU8KOVePggQOZuersFL4kjY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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