SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'afd293e65c742781ba510cc74a22be8bea9989fe1edf85edbb734ab1a0332e6b' 
  AND token = 'ZM0ifQ4qsRl22Sg6bxzysrG3ymWwrPGqSZvxroTP108=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00075

JSON explain

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