SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ba7a0a650b8aa56f13c704cfa5dceaa0b2e73ace5116ee79c4e53cff47f0a177' 
  AND token = 'uuLAV+b0gAqNsY9NP3AaA8eWeWEkfcQmyBiaBWi8Xi0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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