SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '10d3d8f0286af4b75492936c503012cab62dd426f09c1aec98a841d027ffa886' 
  AND token = 'qnLydbTQWSIhQICJAhPrJx9Z1aYE1fbh8qLNz96K6q4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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