SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '14d68e11fb832f04838558c2e009f43697ef8296a722fd321a1c89484c46b1aa' 
  AND token = '+A5sVvLdfVfXI1iGlmnCzVRCOCJ7tTPqMmIQw9qACqA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}