SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'fd57769270edcb5bd8b0302b1feb83c2ccc67cb3484a037e0fd65b1fcd45e1c5' 
  AND token = 'VS4LFCBRZEILj9OmfRe7LCG/zR1/3GBdgzBRzv/qRZ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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