SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75b33f68152fc7538295ba5a0738207568b597c5de873712bc39bd3bfdc80c57' 
  AND token = 'oiInVdCO1zs+beLtcvwTON/1aoa+9/zcR901MfTxPp0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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