SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f0fcbcceb5c3c8258247ffd15af6fe3c10653cc52106634d0a482309a3dd075b' 
  AND token = '21lTqjaHqbqPwcxtuLOFjU45dPa3d2t1DHUOKtzaasI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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