SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b7d1a8afabecb336ce1da9eff73f5cad47b7be2cfb25b8198263fa8666a2202' 
  AND token = 'pvB5Cgu4byYwMjzHh/H0Q9oJaWhk4+9sINHJoC0E7ks=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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