SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b85a34cc0e10ddfa8e1138734e978916a9b8b0528386f0ddfd8f6b0e8eeaf352' 
  AND token = 'VSy3MUBwx4PCtKEnXuNbJyQOhgWXo8ZLRsuA9AH2+8c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}