SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '331d22d16856706a7a26bc953c14df308cdf348a31b7db2429f4b5e964ef8a8c' 
  AND token = 'qpmMDINjrz6s5qHa22mrOv+skCPEvJp/GfswKuvRp4g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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