SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e6fd17b86c5b1bb1a689957999f4edf7cf901601958ba33f17770cd5934e8a9' 
  AND token = 'vyTbwoTE+m6OoHnn3/LbIbZjaa48mEVFEzOrhQWtHuA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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