SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aa92aec66fe6ff730c787026ddc9bb45cb40646570c4507c5e51185bdd065b32' 
  AND token = '2uQUwFEUQR+27Hc3bW54ckhvShQFuEZvtr7Cd0u42Pw=' 
  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"
    }
  }
}