SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4e78134d98545723a2d5ad3f523d4fa64d7e55941b2da222e623b9d7e1d54d2' 
  AND token = 'hFBDeODTURr/p/5NoVb6WPvRNM29nRP3eKwx896cKcY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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